Recently, a technology for capturing a two-dimensional code with a camera, recognizing the code data, and performing predetermined processing associated with that code data has been proposed. Compared to a one-dimensional bar code, a two-dimensional code can store greater amounts of information. Various types of two-dimensional code are put to practical use at present. Accordingly, techniques have been heretofore proposed as to the image recognition of two-dimensional code (for example, see Patent Document 1).
There are various types of measuring systems that utilize magnetic, ultrasonic, or optical means in order to acquire three-dimensional positions, orientations, and the like of objects in real space. Magnetic-based measuring systems are susceptible to the influence of electronic equipment in the environment, terrestrial magnetism, and the like. Ultrasonic-based measuring systems are susceptible to ambient pressures, temperatures, and so on. Optical-based measuring systems, on the other hand, are not susceptible to surrounding magnetic fields, air pressures, temperatures, and the like since they use images captured by a camera. For example, technologies in which a plurality of LEDs arranged on an object are blinked in respective uniquely-defined blink patterns have been proposed. Here, images captured by a two-dimensional image sensor are used to recognize a three-dimensional position and orientation of the object (for example, see Patent Document 2). In the Patent Document 2, LEDs functioning as markers are provided with respective pieces of identification information for unique identification.
[Patent Document 1] Japanese Patent Laid-Open Publication No. 2000-82108
[Patent Document 2] Japanese Patent Laid-Open Publication No. 2003-254716